1. Field of the Invention
This invention relates generally to an electrical component assembly with a heat sink and to a method for providing the assembly, and more particularly, to an electrical component assembly in which a plurality of power transistors mounted on a printed circuit board are thermally connected to a heat sink.
2. Description of the Related Art
Many electrical component assemblies have components, such as power transistors, that generate excessive heat that must be dissipated to avoid degradation to their performance and reliability. The power transistors are generally provided in one or more rows on a circuit board, in physical contact with a heat sink.
Heat sinks of this kind typically include a longitudinally-extending, generally flat mounting surface to which a flat portion of each power transistor is fastened. One or more cooling vanes or ribs typically extend away from the mounting surface. The vanes are typically placed in a location where they will be exposed to open air or to a circulating cool air flow. Because the cooling vanes present an extended surface area to the cool air, the vanes generally will have a lower average temperature than the mounting surface of the heat sink. Because of the temperature differential between the mounting surface and the cooling vanes, heat generated by the transistors is drawn from the transistors to the mounting surface and in turn to the vanes, where it is transferred to the cool air. The heat sink thereby draws out the heat and reduces the temperature of the power transistors from what it otherwise would be.
Power transistors typically have a body portion with at least one generally planar surface. The power transistors are placed in thermal contact with the heat sink by physically attaching them at their planar surface to the heat sink using screws that pass through a mounting flange of the transistor, or through a mounting hole in the transistor body portion itself, and into the heat sink mounting surface. The necessity for physically attaching the power transistors to the heat sink slows down the process of producing the component assembly, and also slows down any disassembly that might be required later. Furthermore, it is usually necessary to provide space for mounting flanges and access to the mounting screws, making the component packaging spatially inefficient.
It should therefore be appreciated that there is a need for a component assembly with power transistors in thermal contact with a heat sink, but with easier assembly and disassembly of the component parts and with more efficient packaging. The present invention fulfills this need.